Cleaning device for dials of telephone instruments



' 1,639,819 1927' G. K. THOMPSON CLEANING DEVICE FOR DIALS OF TELEPHONE INSTRUMENTS Filed Aug. 7. 1925 INVENTOR 6'. E Tim/490.5010

ATTORN EY Patented Aug. 23, 1927..

- UNITED. STATES 1,639,819 PATENT OFFICE.

GEORGE K. THOMPSON, or MAPLEwoon, NEW JERSEY, ASSIGNOR TO AMERICAN TELE- PHONE A D TELEGRAPH COMPANY, A ooRPoRA'rIoN or NEW YORK.

CLEANING DEVICE FOR DIALS OF TELEPHONE INTRUMEN TS.

' Application filed August 7, .1925. Serial No. 48,834. i

This invention relates to automatic cleaning devices more particularly adapted for use in connection with calling devices of telephone instruments of the machine a switching type.

In factories and like establishments, the number plates of telephone instruments are subjected to the accumulation of dust thereon to such eXtent'that the letters and figures 1o appearing on said-plates become indistinct or obscured, and present considerable interference with the proper operation of the instruments.

It is an object of this invention to pro- 15 vide a device which will automatically remove dust and clean the surface of the number plate in an efficient and simplefmanner. A It is a further object of this invention to 2 automatically remove the dust on the number plate in such a' manner that proper operation of the calling device is not interfered with. .Other and further objects will be apparent from the following description when considered in connection with the accom panying drawing in which certain embodiments of the invention are illustrated.

Inthedrawing, in which like reference characters represent like parts throughout,

Figure 1 is a face view of the calling device showing, in dotted lines,,the cleaning attachment applied thereto; Fig. 2 is a side view of Fig. 1; Fig. 3 is a front view of the improved cleaning attachment, and Figs. 4, 5 and 6 'are views similar to Figs. 1,2 and 3, respectively, showing a modification ofthe attachment applied to the instru-- ments in Figs. 4 and 5, and the "modification detached from the instruments in Fig. 6.

Referring to the drawing, 5 represents a form of calling device of the dial type of telephone instrument, by the operation of which impulses may be. transmitted in a manner well understood in the art. The interioinmechanism of the calling device is enclosed within' a casing 6. As this mecha-' nism forms no part of the present invention it need not be described further than to say that it may comprise the usual ele ments well known in the art. A number plate 7 is mounted on one side of the casing 6 and is provided with symbols arranged concentrically about its surface near its periphery. A movable plate or finger wheel 8 is suitably mounted on a-shaft 9 1 above the plate 7 in a plane parallel therewlth and concentrically movable with re.- spect thereto. The finger wheel 8 is provided with a plurality of finger-holes as shown at 10. The symbols on the number plate 7 are in vertical alinement with respect to the holes 10 and may be readily seen beneath these holes.

e A finger stop 11 is shown secured to the. side of the casing 6 and is arranged to engage the finger of the person operating the dial and to thus limit the movements of the finger wheel 8 in a Well known manner.

A punching 12, which may be composed of any flat resilient material, is suitably clamped under the finger wheel 8 and rotates therewith on the shaft 9. A slot 13, whlch 1s provided at one end of the member 12, conforms to the shape of the shaft 9, and is of such size that it rests snugly against the" sides of the shaft when in position thereon. At 1 1 is shown a radial arm which extends from theslotted end 13 toward theedge of the finger wheel 8 at which point it is bent downward at an angle to the plane of said arm, as indicated by the numeral 15.

In Figs. 1, 2 and 3, the punching 12 is shown as extending in the form of an arc 16 from the bent portion 15 to a rounded portion terminating at 17 beneath the finger hole 18. The curved portion 16 is sufliciently wide to cover the portion of the number plate 7 -on which the symbols appear. A stripof fabric 19, such as felt or the like,'is at tached in any suitable manner to the under side of the curved portion and at the top surface of the terminating portion 17 a legend or marking such as Operator or 0 may be applied to the punching. The marking may be covered by a disc of celluloid or the like to prevent the characters from being destroyed through contact with the finger of the person dialing.

In the modification shown in Figs. 4, 5 and 6 a depressed portion '20 is provided between the portion 14 of the arm 12 and the free end 21 in which the hole 22 is provided. On the underside of the depressed portion 20, which is sufiiciently wide to cover the portion ofthe number plate 7 on which the symbols appear, a strip of felt 23 is suitably attached. The free end 21 of the punching Ties against the underside of the finger wheel with the hole 22 in vertical alinement with the finger hole 18 of the fin er wheel. The hole 22, however, is of Bxsmaller diameter than the hole 18 so that when the finger is inserted through the latter the free end of the punching is depressed,

. causing its depressed portion to engage the surface of the number plate 7 in wiping contact.

The calling device above described is operated in the usual manner by placing a \finger in engagement with the finger hole through whiclt is visible the numeral or haracter corresponding to the digit for which it is desired to transmit impulses, and by rotating the finger wheel 8 in a clockwise direction until the finger engages the finger stop 11. The finger is then removed and the finger wheel returns to normal position under the influence of the impulse-sending mechanism enclosed within the casing 6.-

The spring members attached to the movable lates are so adjusted that they normally clear the number plate on which the symbols appear. When, however, the digit zero is dialed, the insertion of the finger in the hole of the finger wheel through which these legends a pear causes the spring'to be dematerial into contact with the number plate when the finger wheel is being rotated clockwise. When the finger is removed, the finger wheel carrying thespring'returns to normal.

- with the number plate so that no variable ,friction, detrimental to the transmission of impulses is introduced during the return of the finger wheel. It will be obvious that by this improved arrangement the wiping pressed,; t ereby bringing the .felt or like I The left or like material is out of contact respect to the number plate,"said finger wheel I being provided with a plurality of finger holes, and means affixed to said shaft and rotatable with said finger wheel to form a wiping contact with the number plate upon the depressionthereof through one of said finger holes.

2. In a-calling device having a number plate, a shaft, a finger wheel rotatably mounted thereon and movable concentrically with respect to the number plate said finger wheel being provided with a plurality of finger holes and means affixed to said shaft androtatable with said finger wheel to form a. wiping contact with the number plate said means being actuated by the depression of one of its ends througli'oneof said finger holes.

plate a finger wheel movable concentrically thereto and means associated with the latter for formi'ng a wiping contact with the number plate upon its depression by the operator in; dialing.

In testimony whereof I have'signe'd my name to this specificationthis 5th day of August, 1925. y

GEORGE K. THOMPSON.

3. In a calling device having a number 

